Zeolite-like compounds, synthesis

Hydrothermal or solvothermal reactions are also an important method for the synthesis of unconventional zeolite-like compounds. The reagents are usually dissolved or dispersed in water and then heat-treated at elevated temperatures in an autoclave. For reactions at moderate temperatures up to about 250 °C the autoclaves are normally lined with Teflon. If higher reaction temperatures are desired, the reactions are, for instance, carried out in stainless steel or gold tubes. However, in favorable cases, the use of higher temperatures might not even be necessary. The products sometimes just precipitate from solution at room temperature. 

Schunk S A and Schuth F 1998 Synthesis of zeolite-like inorganic compounds Molecular Sieves Science and Technology vo 1, ed H G Karge and J Weitkamp (Berlin Springer) pp 229-63... 

Probably the first report on the use of a metaUocene in zeolite synthesis dates back more than ten years [124]. In the past few years, however, essentially two groups reported on the influence (i.e. structure directing properties) of cobalt metallocene compounds in the synthesis of zeolites and zeolite-like materials [e.g. 125-128]. In none of these studies had a new framework topology been synthesized. However, very recently Balkus and coworkers reported the synthesis of the first fourteen-membered ring zeolite, which they called UTD-1 (University of Texas at Dallas No. 1) [129-132]. UTD-1 was synthesized with a quite unusual template, viz. with bis(pentamethyl-cyclopentadienyl)cobalt(III) hydroxide [129-132]. Both the essentially pure-silica version and high-silica derivatives have been prepared. A typical synthesis of the all-silica version com-... 

Schunk SA, Schuth F (1998) Synthesis of Zeolite-like Inorganic Compounds. 1 229-263... 

The trend exists toward merging several steps in a one-pot process, and zeolites, especially, zeolite-like materials (MCM-41, SBA-15, MOFs), are among the key catalysts for such applications. A few examples were provided by Corma et al., for instance, the synthesis of complex amines from aldehydes, amines and acetylenic compounds [201] ... 

Curved structures are not only limited to carbon and the dichalcogenides of Mo and W. Perhaps the most well-known example of a tube-like structure with diameters in the nm range is formed by the asbestos mineral (chrysotil) whose fibrous characteristics are determined by the tubular structure of the fused tetrahedral and octahedral layers. The synthesis of meso-porous silica with well-defined pores in the 2-20 nm range was reported by Beck and Kresge.6 The synthetic strategy involved the self-assembly of liquid crystalline templates. The pore size in zeolitic and other inorganic porous solids is varied by a suitable choice of the template. However, in contrast to the synthesis of porous compounds, the synthesis of nanotubes is somewhat more difficult. 

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